| 摘要 |
PURPOSE:To determine the gamma ray energy spectrum automatically, by using the output of multiple pulse height analyzer as the monitor. CONSTITUTION:When gamma rays are measured by Nal (Tl) scintillation detector and analyzed by a multiple pulse height analyzer, photo peaks of K-40 and Tl-208 appear clearly. However, if a channel to energy calibration curve is obtained from these two points alone, instability may be caused in the low energy region, the when the dose rate is determined by using the calibration curve, an error in the low energy region increases particularly. Instead, therefore, finding stable point (s) in the low energy region besides those two points of calibration, the channel to energy calibration is achieved by the method of least squares using more than two calibration points. Accordingly, a channel to energy calibration device is provided, and noticing that the channel to energy calibration curves A to D are all converged in one point E in the low energy region, this point E is used as the calibration point.
|
